New "mega trucks" - vs - the old "under powered" trucks

My Grandpaw had a 1986 Dodge Ram 1500 2wd w/ a 318 V8 and a 3 spd auto. It reported had 140 HP and 240 LBS torque. He easily towed a 35’ 5th wheel travel trailer on 500 mile trips without a problem.

After that, he had a 1995 GMC 1500 ext. cab 2wd w/ the venerable 4.3L V6 and a 5 spd standard. I see that it had 160 HP and 235 LBS torque. He had a 32’ tongue-pull travel trailer with that. I recall him pulling that trailer in 4th gear going about 55 mph max. He had helper springs and a “tuner” chip on the motor. I don’t know if the chip made a difference.

Pop had a 1986 F150 ext. cab 2wd w/ a 302 V8 and a 4 spd auto. That puppy was cranking out 190 HP and 285 LBS torque. Pop pulled a 28’ travel trailer that was pretty heavy by today’s standards. We weren’t flying down the road like a rocket, but we were rolling pretty good. I don’t recall having a problem.

I see these new trucks out today that with these ungodly amounts of power, and I am sometimes humored by it all. I know it’s marketing, and also the huge HP helps the fuel mileage, but 800 LBS of torque?? My dad has a Ram 3500 4x4 Mega Cab with a 6.7L Cummins. His travel trailer weighs less than the one he pulled with a 302 V8.

It just seems silly to me sometimes. I love the technology, don’t get me wrong. But my neighbor mentioned to me the other day that he needs diesel to haul his bass boat. I laughed pretty hard.

After proofreading this, I realized that my family really likes camping. LOL

Back in 1986 the speed limit was 55. Now it’s 70 or more. That extra 15 mph requires a lot more power.

A 35 foot 5th wheel on a 1/2 ton Dodge? Really? Must have been fun trying to stop that thing.

Must ne one hellofa bass boat…

I agree wholeheartedly with ASE’s thoughts, and would add that drivers today are intolerant these days of a pickup pulling a load that takes forever to get to speed, but I think a lot of it is the “mine’s bigger than yours” motive. Every macho man wants a pickup bigger and badder than his neighbor’s, so the manufacturers make them.

Travel trailers, like cars and trucks have gotten MUCH heavier over the years. I worked with a serious RV-er for many years. His early 32 footers had dual axles and weighed 15,000 lbs or so. His later 35 footers had triple axles and his last 32 footer had dual axles with dual wheels! Eight wheels to hold up about 28,000 lbs or so, He towed that with a Ford 450 diesel 5th wheel.

Your pop must have low standards. I towed a 6000 pound trailer with my 97 F-150 (4.6L 215 HP/290 torque, 3.55 gears, 4 speed automatic), and it was pretty gutless IMHO. For a one time deal, it was tolerable, but If were regularly towing something that heavy or heavier I would get a more powerful/bigger truck.

Also today’s trucks are heavier than they were 30 years ago and the trailers are heavier too.

I’ve been out of the camping scene for a while, but The last one I owned was built in the 80s, and that sucka was heavy for it’s size. it was a 24’ tongue-pull, and it was around 7,500. I thought they’d be getting lighter with newer materials.

@asemaster, I’m sure it was hard to stop. Gramps was a OTR truck driver, so he was pretty careful. I don’t think enough people focus on the stopping and suspension factors when they tow.

@FoDaddy, read the bottom of my post and you’ll see that Dad’s standards have risen as his salary got larger. His ram is like driving a Freightliner. All it’s missing is the air brake sounds.

@asemaster, Also, that 55mph speed limit was a huge factor back then. You’re correct. I recall speedometers having a red line at the 55 marker.

I can’t imagine driving that slow.

I had a work truck once that was a 1996 F250 with a 351 V8 and a factory installed C6 3 spd auto. I have to say, the old vacuum shifted tranny shifted smooth as butter. Much smoother than any electronic ones I’ve had. It was wound up like a weed wacker on the highway though. The constant higher rpms had no detrimental effects that I could see. It had over 200k on it when we sold it, and we abused that heck out of it. She was still running good.

Back in 1972, I bought a Chevrolet 3800 1 ton pickup for $115. I stretched fence with that truck, pulled loaded grain wagons through fields, hauled sand for a horse stall and carried 60 bales of hay at a time. I think that engine had a displacement of 216 cubic inches (maybe it was 235). The low gearing of the truck gave it plenty of grunt for my purposes. This was a real work truck. However, it probably had a top speed of 60 mph. The speedometer didn’t work, so I never really knew. It wouldn’t be suitable for towing anything on the interstate. The trucks that are capable of interstate speeds while towing aren’t work trucks–they are play trucks.

The last truck I had that I’d consider a work truck hauled constantly carried about 2,000 lbs of herbicide application equipment and water in the bed. It went dang fast on the interstate. O/D is a marvelous invention.

I question your definition of “without a problem”. Getting up to highway speed eventually isn’t a real test. Could these vehicles go up a moderate to steep hill without slowing down and holding up traffic? Could they get up to speed in time to merge safely? Could they pass a truck on the highway without creating a rolling roadblock?

Horse power and torque specifications are subject to interpretation. A 1970 Chevrolet 350 gasoline engine in Corvette had 370 horse power at 6,000 rpm and 380 lb/ft of torque at 4,000rpm. The medium duty truck version of that engine was rated at 215 hp at 4,400 rpm and 320 lb/ft of torque at 2,400 rpm. The Corvette’s 370 horse power was for momentary high performance driving similar to “take off” power on piston airplane engines. On the other hand the truck engine was expected to operate at that maximum rated horse power continuously.

I recall long ago driving a Chevrolet bob truck with a 24 ft refrigerated box loaded with milk, powered by a 292 cu in 6 cylinder engine rated at 170 horse power that could maintain 80 mph on level roads. On long uphill grades it was necessary to downshift and the speed would drop to about 60 mph. Getting it up to speed when fully loaded required churning through the 5/2 gear box though. When engines advertise horse power greater than 60 per liter(1 hp/cu in) the power is there if needed for wide open throttle passing, not sustained operation. Or so it seems to me.

The 1970 Corvette HP was also gross HP with every accessory and the mufflers disconnected. Actually it was more like an SAE net 275 HP at the flywheel. This engine was cammed to make power peak at 6000 rpm and wasn’t suitable for truck use for that reason.

Compare that to today’s smaller 5.3 liter (327 ci) smallblock making 355 net hp at only 5300 rpm, 383 ft-lbs of torque and getting 20 mpg highway in a 5300 lb truck!

No doubt, the camshaft is the only significant mechanical difference in the 2 350 engines that I compared @Mustangman, but the relative difference in those engines’ power bands was designed in to suit their use, and does Chevrolet expect that the current 5.3liter engine to operate continuously at its maximum rated output? And also, what would the output be on that 5.3 liter if it were cammed out for 6,000 rpms? With its computer optimized fuel injection and timing it would possibly exceed 400 hp.

My observations of engine performance over the years leads me to believe that an engines peak performance is approximately at the peak of the torque curve. When driving fully loaded trucks the best acceleration can be had by up shifting at the speed that results in the rpm being at maximum torque when the clutch is released in the next range. Pushing the engine to the red line before shifting usually results in longer 0 to 60 time than using the seat of your pants to feel when the rpm in one range will result in hitting that “sweet spot” in the next range. Of course that’s old school since even the semis today use computer controlled automatic transmissions that shift at the ideal rpm based on demand, do any of them run the rpm up to the red line?

@“Rod Knox” The current Gen V LT-1 5.3L already has 355 HP stock. it would not take much to get 400 HP out of one. It also has variable valve timing (despite being an OHV engine), you can be pretty flexible with the cam selection.

@Rod Knox I had a similar discussion many times with my RV buddy. Our take is that HP is for speed and torque is for acceleration. Torque provides the “push” you feel and the grunt that gets your trailer up a hill. For trucks the HP isn’t as important as torque. If you can get the trans to downshift so the rpm is just past torque peak, as the truck climbs the hill it falls back to the torque peak as it slows a bit and maintains speed if there is enough torque. If not, it downshifts and revs away and tries again.

So yes, I think your observation is correct, the max measured (and felt) acceleration is peak torque, not peak HP. The higher the HP, the higher the torque stays as the rpm rises past peak torque, that’s just the math of it. Running to redline is just to get the revs up enough to be at peak torque in the next gear up. If you have more gears, you don’t have to rev it that high.

And yes, the current 5.3 likes more cam. They have very mild cam timing from the factory. I’ve read a couple of articles where changing cams nets 400 hp in a 5.3 very easily. You do lose a little low rpm torque. The heads flow so well and the lack of internal friction in these engines mean they can make tons of HP.

In the 50s you didn’t expect to get up a hill without losing speed when towing with a pickup truck. And speed limits were higher then before the double nickel came in.With tractor trailers through the 80s we slowed to 15 mph on hills on US 15 through Pennsylvania. It is more a difference of expectation than need. Most 2 lane highways have an added right lane up steep hills for slow moving vehicles.

That old 292 cid chevy engine was a brute,some of the older Chevy trucks had 235 cid and the babbit rod engine was 216 cid,long about the mid fifties the venerable"stovebolt six"could reach 261 cid, todays drivers are spoiled by the power at their command,I would like to see what a proportional sized truck mileage could be if they were designed properly.It seems now most things are judged by the the Gs they generate on launch,torque and horsepower are related in piston engines at a certain rpm the the lines cross on the graph,a truer rating of an engines output in my estimation is kw,most people do not pull 20K trailers(you have to stop the thing too)Not so long ago,pickup engines werent nearly as powerful,I guess the champ would be electric motors if you could supply them with enough electricity(at least you wouldnt have to worry about alcohol in the fuel)And trucks do need high torque rise(so you dont have to have such a complicated gearbox-remember some of the largest trucks and such in the world are electric drive,how they generate the electricity is another matter,seems to me like thats a marriage made in heaven,cycle the ICE at its most efficient range to generate the electricity for the electric drivetrain(yech,just watched a Tesla smoke a Hellcat again(for the second time) in the 1/4 mile,looks like we could find some common ground.
One nice package really has my interest now and its the new Dodge 1500 eco diesel(Ram I guess sorry)plenty of grunt and capable of 30 mpg on the highway(I do not mind adding a little diesel fluid from time to time)So we can have our cake and ice cream too.

Low speed torque gives good towing capability and those old engines had lots of that.

A lot of the difference is in engine management.

On an old-school engine (meaning carbs, mechanical timing advance, no cam adjustments) you could optimize an engine for high-rpm OR low-rpm. Witness hot rods with “racing cams” that can barely idle! Given the workmanlike duty of old trucks, they were invariably optimized for low RPM.

What that means, is that the large-displacement iron pulled like a much more powerful modern engine…they just fell on their face at about 3000 RPM or so. Given that 95% of your duty cycle is <3k, not that big of a loss. Modern computerized controls allow “best of both worlds,” so a modern truck engine might close to double old-school iron output (at 6,000 RPM), but the torque/HP curves will look eerily similar at stump-pulling speeds.

Some of the old trucks were more fun. The 396 guys all had Holley Spread Bores, Edelbrock intakes, headers and RV camshafts. The Ford guys were less fun and did no modifications at all but hauled the same loads. Pickups are not just vehicles, they’re attitudes.